Hello Dr. Rao, this is Dr. Singh. I read your presentation. It is nice and informative. I want to give a lecture on this topic on Acinetobacter baumannii. Can you please me these slides. My email is; piarausa@hotmail.com

Transcript

Acinetobacter baumannii is a ubiquitous pathogen capable of causing both community and health care–associated infections (HAIs), although HAI’ s are the most common form. This organism has emerged recently as a major cause of HAI because of the extent of its antimicrobial resistance and its propensity to cause large, often multifacility, nosocomial outbreaks.

Since the 1970s, the spread of multidrug-resistant (MDR) Acinetobacter strains among critically ill, hospitalized patients, and subsequent epidemics, have become an increasing cause of concern. Reports of community-acquired Acinetobacter infections have also increased over the past decade. A recent manifestation of MDR Acinetobacter that has attracted public attention is its association with infections in severely injured soldiers.

The genus Acinetobacter comprises 17 validly named and 14 unnamed (genomic) species. Some unrelated (genomic) species have common designations, while some other species seem to be congruent but have different names. A phenotypic species identification system has been described and a variety of genotypic methods has been explored and applied to investigate the diversity or phylogeny in the genus.

The name, Acinetobacter , comes from the Latin word for &quot; motionless,&quot; because they lack cilia or flagella with which to move. Most species are not significant sources of infection. However, one opportunistic species, Acinetobacter baumannii , is found primarily in hospitals and poses a risk to people who have supressed immunity:

According to the CDC, A. baumannii causes 80% of all Acinetobacter infections

Methods include high resolution fingerprinting with AFLP, PCR-RFLP with digestion of PCR amplified sequences, and analysis of various DNA sequences. Of these, AFLP analysis and amplified 16SrRNA ribosomal DNA restriction analysis have been validated with large numbers of strains of all described species. Nucleotide sequence based methods are expected to be the standard for identification in the near future.

Acinetobacter baumannii is a bacterium in the Acinetobacter genus which can be dangerous for human beings who have compromised immune systems , causing opportunistic infections which can lead to death if the patient does not receive aggressive treatment.

The organism can survive for months on clothing and bedclothes, bed rails, ventilators and other surfaces in the environment, including sinks and doorknobs, making Nosocomial transmission extremely difficult to control.

A well-characterized porin of A. baumannii , the 38-kDa outer membrane protein A, has been shown to induce apoptosis of eukaryotic cells and to activate dendritic cells, leading to the differentiation of CD4+ T cells toward a Th1 phenotype

Some nurses, soldiers, and microbiologists infected with Iraqnobacter (Acinetobacter baumanii ) due to its spread throughout the military hospitals. Many times soldiers have survived hellacious trauma on the battlefield only to succumb to even more damage by an organism that has picked up antimicrobial resistance factors to the drugs primarily associated with treating them almost impossible.

Acinetobacter commonly colonizes patients in the intensive care setting. Acinetobacter colonization is particularly common in patients who are intubated and in those who have multiple intravenous lines or monitoring devices, surgical drains, or indwelling urinary catheters..

Acinetobacter causes colonization more often than infection; this means that it lives in or on the body without causing illness (e.g., the skin of a healthcare worker). People who are colonized can become carriers who spread the bacteria to other people, usually without realizing it.

The respiratory system is the most common site for Acinetobacter infection because of its transient pharyngeal colonization of healthy persons and a high rate of tracheotomy colonization. Acinetobacter has been reported to cause community-acquired bronchiolitis and tracheobronchitis in healthy children.

Infection or colonization with Acinetobacter is usually diagnosed by clinical culture of blood, sputum, urine, wound, sterile body fluid, etc. Microbiologic cultures can be processed by standard methods on routine media.

Acinetobacter baumannii isolates were presumptively identified by using morphology of the colonies, Gram staining, Oxidase and Catalase reactions, growth at 44°C, and the API-20 NE System (Bio-Merieux, Lyon, France) Identification as A. baumannii was verified by restriction analysis of the 16S-23S ribosomal RNA intergenic-spacer sequences, ( described by Dolzani and colleagues)

One of the biggest issues with treating Acinetobacter baumannii is that the bacterium is naturally resistant to a number of antibiotics, making it challenging to find a drug regimen which will effectively attack it in an infected patien

The elucidation of potential risk factors for resistant strains of Acinetobacter is therefore an important task, and the use of alternative antibiotics should be considered in ICUs where these strains are endemic .

Multidrug-resistant A. baumannii is a common problem in many hospitals in the US and Europe. First line treatment is with a Carbapenems antibiotic such as imipenem , but carbapenem resistance is increasingly common. Other treatment options include Polymyxin, tigecycline and Aminoglycosides.

Colistin and Polymyxin B have been used to treat highly resistant Acinetobacter infections. The choice of appropriate therapy is further complicated by the toxicity of colistin which is mainly renal. Acinetobacter isolates resistant to colistin and Polymyxin B have also been reported .

Recently A. baumannii has also been seen in a number of wound infections in soldiers returning from the middle east. Wound infections in soldiers is not a new phenomenon for A. baumannii as it was the most common gram negative bacillus to contaminate wounds during the Vietnam war as well.

Since Operation Iraqi Freedom began in 2003, more than 700 US soldiers have been infected or colonized with Acinetobacter baumannii. A significant number of additional cases have been found in the Canadian and British armed forces, and among wounded Iraqi civilians.

Where the Iraqibacter came from remains something of a mystery. Soil samples taken by researchers in Iraq and Kuwait came back negative. However, it was found thriving in the hospitals. When Iraqibacter was compared to MDRAB samples taken in Europe before the war, they were found to be identical (Silberman, 2007). Thus, scientists believe that the current outbreak originated from European sources.

Should be followed at all times. As with prevention of any healthcare-associated organism, careful hand hygiene should be performed at all appropriate times– either hand washing at the sink or using an alcohol based hand sanitizer. Contact precautions are indicated. They should be maintained for the duration of hospitalization or until negative cultures are obtained.

1 Institution of active surveillance of groin, axillary, and/or wound cultures for A. baumannii for all patients; 2) use of contact precautions for colonized or infected patients; and 3) increased availability and use of alcohol-based hand rubs.

Acinetobacter can live on the skin and may survive in the environment for several days. Careful attention to infection control procedures such as hand hygiene and environmental cleaning can reduce the risk of transmission.